Vehicle control method and vehicle warning method

ABSTRACT

In order to occur a collision warning to prevent the collision in accurate by detecting the preceding vehicle or target, a vehicle lane position estimation device comprising a means for measuring a distance between said host vehicle and said preceding vehicle or a oncoming vehicle, a direction angle from said host vehicle, an angular velocity and a velocity of said host vehicle, a means for calculating lateral and longitudinal distance between said host vehicle and said preceding vehicle or said oncoming vehicle, a means for capturing a front stationary object, a means for obtaining movement of the preceding vehicle or position of the oncoming vehicle, and a means to estimate a lane position of said front stationary object from a relationship of the stationary object being captured and the preceding vehicle being obtained and a positional relationship with the oncoming vehicle.

BACKGROUND OF THE INVENTION

[0001] [The Technical Field that the Invention Belongs to]

[0002] The present invention relates to an estimation device using aradar to detect dangerous objects for a vehicle.

[0003] Especially the present invention relates to the estimation devicefor distinguishing various kinds of non-dangerous objects which aregenerally met in typical vehicle driving environment and the dangerousobjects which are authenticity.

[0004] [Prior Art]

[0005] A lot of trials to discriminate the dangerous objects that can betrusted, were performed in a field of a vehicle radar system to measurea distance to the dangerous objects and a relative velocity thereof.

[0006] In a Japanese Patent Laid-open No. 6-282798 bulletin, a targetsearch device is mentioned, the target search device comprising a targetcapture means to capture the target by searching periphery of a servicebody and to get a relative position of the target to the service body, acircular orbit estimation means to estimate a circular orbit of theservice body in a turning motion of the service body, based on therelative position of the target which the target capture means got andthe circular orbit of the service body (4) which the circular orbitestimation means estimated, and a control means to judge whether thetarget is located in the circular orbit and to distinguish the targetlocated on a course of the service body.

[0007] In a Japanese Patent Laid-open No. 8-83400 bulletin, a method todistinguish dangerous objects for the vehicle from the objects which isnot the dangerous objects in the vehicle radar system which can detectat least one object on the road near the vehicle driving in the firstvehicle lane is mentioned, said method comprising the steps of a step togenerate a radar beam having enough beam width to irradiate the objectin the first vehicle lane and a second vehicle lane which is nextthereto, and at least a part of the radar beam generated along a firstaxis which is generated in a right angle substantially, a step toreceive a message of a reflex signal from the object irradiated, a stepto estimate a velocity of the object irradiated about a vehicle velocityin a direction of the second axis (x) which is substantially parallel tothe service direction of the vehicle based on reflection signal, a stepto measure the velocity of the vehicle using at least one velocitysensor, a step to judge the irradiated object to be dangerous when a sumof measured the vehicle velocity and estimated the velocity which isparallel to the object is bigger than a predetermined threshold, and astep to judge the irradiated object not to be dangerous when a sum ofmeasured the vehicle velocity and estimated the velocity which isparallel to the object is smaller than the predetermined threshold.

SUMMARY OF THE INVENTION

[0008] [The subject that Invention is Going to Solve]

[0009] A sensing requirement for a system should be thinking about asthat a distance with a preceding vehicle(including stopping vehicle andan object, herein after called as a target) is controlled to be adesired value (ACC: Adaptive Cruise Control) by detecting the lead carin forward of host vehicle lane, or a collide warn is occurred whencoming too much close to the preceding vehicle or the target.

[0010] For example, following three phases may be considered.

[0011] The first step: A detectivity ability, that is, may the forwardtarget (the vehicles and road side object) be recognized?

[0012] i) A distance to the target (max especially), relative velocityand detectivity power of angle.

[0013] ii) An accuracy of the vehicle lane judgment of the host vehiclelane/others vehicle lane.

[0014] The second step: Discrimination ability, that is, may the forwardtarget be recognized?

[0015] Especially, is the forward stationary object in forward of thehost vehicle discriminated? (For example, the road side object such as astationary vehicle, a corner pole and road signs, and an object on theroad such as an overhead bridge can be distinguished?)

[0016] The third step: Intention decision, that is, which direction isthe driver going to go to?

[0017] Is the forward obstacle included in a driving path in the futurebased on the driver intention? (there is no need to occur the warningwhen not included.)

[0018] Referring to the above, an object of the present invention is toprovide a vehicle lane position estimation device of the precedingvehicle or the target by improving the vehicle lane decision accuracy ofthe host vehicle lane/others vehicle lane and by detecting the precedingvehicle in forward of the host vehicle lane or the target, so that thedistance with the preceding vehicle is controlled to be a desired valueor a collision warning to prevent the collision with the target isgenerated in accurate.

[0019] Further, another object of the present invention is to provide avehicle lane position estimation device of the forward stationary objectwhich may recognize in accurate whether the stationary object is adangerous objects on the host vehicle lane or not or whether it is onthe host vehicle lane or not.

[0020] Further, another object of the present invention is todistinguish the stopping preceding vehicle and the stationary objectsuch as a road sign on the road side or an overhead bridge, and to warnor control (decelerate) the stopping vehicles which is in forward of thehost vehicle.

[0021] [A Means to Solve the Subject]

[0022] According to the present invention, algorithm for estimating thehost vehicle lane to be accurate in a curved road and for estimating anaccurate correction when a position correction is necessary, is providedon the basis of a movement of the preceding vehicle which the radarcaught and other sensor information, various data from the vehicles sideare received, vehicle lane position estimation of the preceding vehicleis performed with a sensing information got by a millimeter wave radar,and a one body type millimeter wave radar system is built in acommunications network function that can transmit an warning or acontrol command information to the vehicle side and decision/controlfunction, is provided.

[0023] In such the vehicle lane position estimation device as above, thepresent invention further comprising a means for judging whether a curveof said road is a transition curve section where a curvature radiusthereof changes every moment sometimes, or a maximum curve section wheresaid curvature radius does not changes, and a means for correcting acurvature radius Rf of said host vehicle used for correcting saidcurvature radius Rf of said preceding vehicle to be smaller than apredetermined value when a transition curve is in an introduction partof the curve, and for correcting said curvature radius Rs to be largerthan said predetermined value when said transition curve is in an rearpart of the curve.

[0024] In such the vehicle lane position estimation device as above, avehicle lane boundary position is obtained by estimating a vehicle laneposition of plural preceding vehicle, the host vehicle is judged to beright or left of the vehicle lane boundary, and a vehicle lane judgmentposition of said host vehicle is offset towards right or left.

[0025] In such the vehicle lane position estimation device as above, thepresent invention further comprising a millimeter wave radar and a gyrosensor are used as said means for measuring.

[0026] In such the vehicle lane position estimation device as above, thepresent invention further comprising a means obtaining a distance of thevehicles from said preceding vehicle, and a means for warning when saiddistance becomes a predetermined distance.

[0027] The present invention relates to a vehicle lane positionestimation device for estimating a position of a vehicle lane of astationary object (a forward stationary object) to be located before anhost vehicle, comprising a means for measuring a distance between saidhost vehicle and said preceding vehicle or an oncoming vehicle, adirection angle from said host vehicle, an angular velocity and avelocity of said host vehicle, a one vehicle lane sensing means forobtaining a vehicle lane of a road, a means for calculating a lateraldisplacement between said host vehicle and said preceding vehicle orsaid oncoming vehicle, a longitudinal displacement therebetween and acurvature radius of said host vehicle, a means for capturing a forwardstationary object, a means for obtaining a movement of said precedingvehicle or a position of said oncoming vehicle, a means for estimating avehicle lane position of said forward stationary object from a movementrelationship of said preceding vehicle obtained and said forwardstationary object captured or a position relationship with said oncomingvehicle, and a means for warning when said forward stationary object isin a vehicle lane of said host vehicle.

[0028] In such the vehicle lane position estimation device as above, thepresent invention further comprising a means for recognizing whethersaid forward stationary object is an object on the road such as anoverhead bridge.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029]FIG. 1 is a contour block diagram of a distance between vehiclesalarm system.

[0030]FIG. 2 is a contour block diagram of an ACC system.

[0031]FIG. 3 is a control block diagram.

[0032]FIG. 4 is a figure of account system.

[0033]FIG. 5 is a curvature radius illustration.

[0034]FIG. 6 shows related figures of the curvature change and thecorrection.

[0035]FIG. 7 is a figure of a flow chart of a correction step.

[0036]FIG. 8 is a contour block diagram of a distance between vehiclesalarm system.

[0037]FIG. 9 is a contour block diagram of the ACC system.

[0038]FIG. 10 is illustration to discriminate an overhead bridge and astopping vehicle.

[0039]FIG. 11 is a contour block diagram of a distance between vehiclesalarm system.

[0040]FIG. 12 is a contour block diagram of an ACC system.

[0041]FIGS. 13A and 13B show figures to discriminate a curve and avehicle lane change of a preceding vehicle.

[0042]FIG. 14 is a flow chart of the discrimination method.

[0043]FIG. 15 is a flow chart of host vehicle lane position estimation.

[0044]FIGS. 16A and 16B show figures of the preceding vehicle and thestationary object recognition and moving velocity.

[0045]FIG. 17 is a figure of transverse direction transfer of the curveand the vehicle lane change.

[0046]FIG. 18 is a figure of the oncoming vehicle and the stationaryobject recognition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0047] An embodiment of the present invention will be explained based ona drawings.

[0048]FIG. 1 shows a distance between the vehicles alarm system 1 usinga millimeter wave radar, a gyro sensor, or a steering sensor.

[0049] The figure shows a system configuration in a case that amillimeter wave radar signal is generated from a radio antenna unit 4toward a vehicle 3 from a host vehicle 2, and warn when approaching.

[0050] The distance between the vehicles•the relative velocity•the anglewith preceding vehicle 3 is measured with a unit 5 by a conventionalmethod using a radio antenna unit 4 of the millimeter wave radar.

[0051] Measurement is performed with a unit 8 by measuring the angularvelocity by a gyro sensor 6, and the steering angle is measured bysteering sensor 7 with a unit 9.

[0052] By the measured angular velocity and the steering angle, avehicle lane is judged with a unit 10 according to an algorithmmentioned later.

[0053] The preceding vehicle judgment with a unit 11 and stationaryobject judgment with a unit 12 in forward of the host vehicle areperformed by the distance between the vehicles•the relativevelocity•angle (preceding vehicle 3) which are measured and vehicle lanejudgment.

[0054] Based on these judgments, an warning judgment with a unit 14 isdone by using the warning judgment algorithm with a unit 13, and avehicle velocity and a braking signal with a unit 26.

[0055] Based on the warning judgment, an warning designation with a unit15 is performed, and an alarm signal 16 is given, and an alarm soundgeneration, lighting and display are performed in a driver display unit17.

[0056]FIG. 2 shows an other embodiment of the present invention, using amillimeter wave radar, a gyro sensor, or a steering sensor.

[0057] ACC system 21 is shown to drive following a preceding vehiclekeeping a predetermined distance between the vehicles.

[0058] A millimeter wave radar signal is given from a radio antenna unit4 toward a driving vehicle 3 from the host vehicle 2, a precedingvehicle detection with a unit 22 and a stationary object sensing 23 areperformed by measuring the distance between the vehicles•the relativevelocity•the angle and the vehicle lane judgment.

[0059] Based on these sensing, an accelerating and a deceleratingjudgment with a unit 25 is done by using the distance control algorithm24 between the vehicles, a vehicle speed signal, and a braking signal26.

[0060] Based on the judgment result, a vehicle speed holding and theaccelerating/decelerating speed signal are given with a unit 27, thedistance control between the vehicles with a unit 28 comprising aslottle control 29, a A/T shift control 30, and a braking control 31 isdone.

[0061] In addition to above, the system of FIG. 1, FIG. 2 namely alarmsystem and an ACC system do not always exist only as separated system,but a system configuration having both function can be taken.

[0062] In next, FIG. 3 shows a hardware configuration to realize anembodiment of the system by FIG. 1 and FIG. 2 with a block diagram.

[0063] The construction shown in the figure are a one body typemillimeter wave radar system 35, a vehicles side control part 36, and adisplay unit 37 for a driver.

[0064] The one body type millimeter wave radar system 35 has, forexample, a communication network facility that used CAN, for example,and is constituted with a vehicles side control part 36, a driverdisplay unit 37 and a communications network.

[0065] In the figure, a radar sensing signal obtained by a transmittingantenna 41 built in a unit 35, a receiving antenna 42 and a highfrequency circuit 43, and an analog signal from the gyro sensor 6 areconverted by an AD conversion 44, and are done signal processing by adigital signal process circuitry 45 (constituted with CPU, DSP etc.)

[0066] Said digital signal process circuitry 45 is installed a softwareas built-in software 47, in order to process a risk judgment and anwarning order in an warning and an ACC following order and anaccelerating deceleration orders ets. in the ACC based on the radarsignal processing, preceding vehicle trapping, host vehicle lanejudgment, etc.

[0067] As for these various signals, they are communicated through acommunications network 38 and a data communication part 46.

[0068] The driver display unit 37 generate the alarm, do lighting anddisplay the distance with the preceding vehicle according to acommunication signal received.

[0069] According to setting modification of the driver to reverse, anadjustment of the distance that the warning occurs in the warning isperformed, and the adjustment signal of the distance between the hostvehicle and the preceding vehicle in the ACC is transmitted to the unit35. In the digital signal attention circuitry 35, modification of thevarious parameter is enforced based on said adjusting signal.

[0070] The vehicle side control part 36 is used in order to constitutethe ACC system.

[0071] This is constituted with an engine control unit 51, an AT controlunit 52 and a braking control unit 53, the engine output, the AT shiftposition, and the automatic braking in order to slow down suddenly areperformed in order to accelerate and to decelerate the vehicle byreceiving a signal from the one body type millimeter wave radar system35.

[0072] The vehicle side control part 36 is inputted various sensorsignals which are necessary for controlling in the vehicle side, forexample, a gyro sensor signal 6, a steering sensor signal 7, a vehiclespeed sensor signal 26, a braking signal 260, a wheel velocity sensorsignal 54, a shift position sensor signal 55, an acceleration sensorsignal 56 etc.

[0073] And, the signals which are necessary for the one body typemillimeter wave radar system 35 side, for example, the vehicle velocitysensor signal 26 and the steering sensor signal 7 are transmittedthrough a communications network 38.

[0074] In these system configuration, as the vehicle side control part36 is a conventional technique and it is not described moreover indetail.

[0075] In next, in said built-in software 47, a method to judge vehiclelane in a curved road and a derivation of operating equation will beexplained.

[0076]FIG. 4 shows a relationship between a own car which is on a circlecontour of a curvature radius Rs and a lead car which is on Rf.

[0077] Judging from the host vehicle, whether the preceding vehicle ison the host vehicle or on an adjacent vehicle lane, can be judged by adifference ΔR of the curvature radius between the host vehicle and thepreceding vehicle originally.

[0078] Method of operation will be explained as follows.

[0079] 1. A distance Tr and a magnetic declination degree α are measuredby using the millimeter wave radar, and a host vehicle angular velocityωs and a host vehicle velocity Vs is measured with the built-in gyrosensor 6.

[0080] 2. A side displacement TC, a longitudinal displacement TD and ahost vehicle curvature radius Rs are calculated with the next equations.

T _(C) =T _(R) sin α,

T _(D) =T _(R) cos α,

R=Vs/ωs

[0081] 3. As shown in FIG. 4, as for the rotation radius Rf of thepreceding vehicle, the next equation is obtained.

Rf ² =Rx ² +TD ²=(Rs−TC)² +TD ²

[0082] 4. Therefore, the next equation is obtained.

[0083] [Equation 2]

ΔR=Rf−Rs={square root}{square root over ((Rs−Tc)2+Td2−Rs)}  (Equation 2)

[0084] Here Ly is defined as a vehicle lane width.

[0085] [Equation 3]

|ΔR|<Ly/2(Ly: one vehicle lane)  (Equation 3)

[0086] The vehicle lane of the host vehicle is judged when the aboveequation is satisfied.

[0087] The value of Ly is not be a half vehicle lane width which issymmetric for an host vehicle because the host vehicle may not go on acenter of the vehicle lane.

[0088] The setting method of the value is disclosed in an embodimentexplained later.

[0089] Using FIG. 5 and FIGS. 6A, 6B in the next, a correction method ofthe curvature radius Rf of the preceding vehicle will be explained.

[0090] Currently, the position of the preceding vehicle in a curved roadis estimated by correcting on the basis of the angular velocity measuredwith the gyro sensor.

[0091] In this correction method to use the angular velocity of the hostvehicle, the preceding vehicle is calculated to be on a circle extendedfrom a rotation center of the position which is same as the current hostvehicle.

[0092] However, a real road does not consist of only a linear lane and acurve lane, and “a transition curve” section which is joinedtherebetween by changing R by degrees exists by all means.

[0093] Accordingly, even if it is assumed that the angular velocity ismeasured good enough in accurate, a right measurement is only performedwhen both of the preceding vehicle and the host vehicle is in a circlecontour or a linear line.

[0094] Accordingly, it becomes important that this transition curve isdetected and the R is corrected in suitable.

[0095]FIG. 5 shows a transition section 62 connected to a linear linesection 61, a constant R section 63, a transition section 64, and alinear line section 65 connected to said transition section 64.

[0096] In other words, the R becomes small (the angular velocityincreases) in the transition section 62 by degrees, the R becomesconstant (angular velocity constant) in the constant R section 63(circle contour section), the R increases by degrees (angular velocitydecrease) when coming in a reverse transition section 64, and it isreturned to a linear line section (In the linear line, R=∞).

[0097] Accordingly even if it is assumed that the preceding vehicle andthe host vehicle ran at the same vehicle lane center, when the hostvehicle is on the transition section 62, the preceding vehicle travelson the small R than this section 62, and reversely, when the hostvehicle is on the transition section 62, the preceding vehicle travelson a bigger R than a detected R of the host vehicle.

[0098]FIGS. 6A, 6B shows a change of the angular velocity ωR, a changeof the curvature radius R, and a correction direction of the R detectedwhen driving the curve.

[0099] Shown in the figure, the R is corrected in the transition section62 a little to be (R−ΔR) , the R is constant in the constant R section63, the R is corrected greatly in the transition section 63 as (R+ΔR) soas to estimate the lane of the preceding vehicle.

[0100] Here, it is assumed that the preceding vehicle is followed by astatus without relative velocity with the host vehicle.

[0101] Then the R is corrected using sensor information such as

[0102] 1. A distance d with the preceding vehicle, and a magneticdeclination θ and The change Δθ,

[0103] 2. an angular velocity ωR every moment, and a change ΔωR thereof,

[0104] 3. a steering angle φ and a change velocity δφ thereof.

[0105]FIG. 7 is a flow chart showing a correction step.

[0106] At first, in a step 701, a distance d(t) with the precedingvehicle at a time t, the preceding vehicle magnetic declination θ(t),the angular the velocity ωR(t) and the steering angle φ(t) is detectedand is stored.

[0107] In a step 702 in the next, a change Δθ(t), ΔωR(t) and (δφt) ofθ(t), ωR(t), φ(t) are obtained by performing a differentiation filterprocessing using past time t-1, t-2, . . .

[0108] In a step 703, absolute values |Δθ(t)| and |δφ(t) | of the Δθ(t)and δφ(t) are judged.

[0109] When the absolute values are changed greatly together, it istaken as a vehicle lane change and it is taken off from an object to becorrected (step 704).

[0110] On the other hand when it is not judged so, it is taken as theobject to be corrected.

[0111] In a step 705, plus and minus of Δ107 R(t) are judged. In case ofΔωR>0, the host vehicle is judged to be in the transition section 62,and the R is corrected to be small as (R−ΔR) (step 706,).

[0112] In a case of ΔωR<0, the host vehicle is judged to be in thereverse transition section 64, and the R is corrected to be large as(R+ΔR) (step 707).

[0113] In a case of ΔωR=0, the host vehicle is judged to be in thecircle contour section 61, and the R is not corrected (step 708).

[0114] By the way, in a case that an warning and a ACC system areconstituted with a millimeter wave radar as a key sensor, there arecomparatively a few problems about a moving object such as the precedingvehicles driving.

[0115] However, in a case to perform the warning for forward stationaryobject or the ACC deceleration control, the millimeter wave radar canmeasure the distance with a target, a relative velocity and angle inaccurate, but it is difficult to recognize what it is.

[0116] For example, when there is a curve in a forward direction, evenif it is assumed that a stationary object is caught on a forward drivingdirection, it is difficult to judge whether it is a stopping vehicle onan host vehicle lane or a road sign installed on the road side and overthe road.

[0117] In this way, the case that cannot be judged only with themillimeter wave radar exists sometimes.

[0118] So in FIG. 8, in order to judge the warning for the stationaryobject precisely, an embodiment is provided which has a CCD camera beinganother kind of a sensor in an embodiment of FIG. 1.

[0119] The same numerals are referred to the constitution to be same asthe constitution of an embodiment shown ahead in order not to repeat thesame description.

[0120] The figure shows a distance between the vehicles alarm system 70constituted by using signals from the millimeter wave radar, the gyrosensor, the steering sensor and the CCD camera.

[0121] In the figure, the CCD camera 71 is used for white linerecognition 72 usually by a photography pictorial image thereby, and hasa zoom lens function.

[0122] On the other hand, the millimeter wave radar performs astationary object sensing from a distance, a relative velocity and anangle.

[0123] When the millimeter wave detects the stationary object 23 forwardnow, the camera stops a white line recognition 72 temporarily and zoomup the forward stationary object which the millimeter wave caught.

[0124] The stationary object recognition 73 is performed, and whether itis an obstacle such as the stopping vehicle or not, and whether it isnon-obstacles such as a road sign outside of the road and an overheadbridge or not are judged.

[0125] Based on this stationary object recognition, the warning judgment14 is performed, an warning designation 15 for a stationary object isperformed and an alarm signal 16 is given to a driver display unit 17.

[0126]FIG. 9 shows an ACC System 75 similarly using signals from themillimeter wave radar, the gyro sensor, the steering sensor and the CCDcamera.

[0127] In the same way as the FIG. 8, a stationary objectsensing—recognition is performed, and an accelerating and deceleratingjudgment 25 of the vehicle is performed based on a signal from thestationary object recognition 73 (A reducing speed judgment for thestationary object).

[0128]FIG. 10 shows a case to distinguish the overhead bridge and thestopping vehicle as one example of the stationary object.

[0129] The millimeter wave radar detects the overhead bridge in aconsiderably forward position, 100-150 [m] ahead numerically.

[0130] In this period, it cannot be distinguished whether the forwardstationary object is the overhead bridge or the stopping vehicle.

[0131] When the detected stationary object is the stopping vehicle, itbecomes necessary to warn in this period because it takes much time forthe deceleration in a high-speed driving with more than 100 km per anhour.

[0132] Then, whether it is the overhead bridge or the road obstacle suchas the stopping vehicle, is judged by performing the image processingusing the camera. The image processing means to distinguish the targetby a pattern matching and a sensing accuracy is not demanded so much.

[0133] As a result of discrimination, when it is taken as the overheadbridge, the alarm is not outputted.

[0134] In this way, it becomes possible to improve the accuracy of thewarning by combining the target sensing by the millimeter wave with thetarget discrimination by the camera image processing.

[0135] By the way, if it is assumed that the forward stationary objectis discriminated and it is the obstacle such as the stopping vehicle onthe vehicle lane, they are not complete as a judgment object foroutputting the warning.

[0136] For example, in a cases that there is a branching road forward,and there is a stopping vehicle on one side thereof, an accuratejudgment whether the warning should be outputted is not performed if itis not understand which course the vehicle selects.

[0137] Then, in FIG. 11, a distance between the vehicles alarm system 76constituted by using a signal from a navigation system in addition tothe millimeter wave radar, the gyro sensor, the steering sensor, and theCCD camera. In the figure, a path judgment 78 is performed by using thenavigation system 77.

[0138] With the sensor except the navigation system, the stationaryobject sensing and the stationary object recognition are performed, andit is assumed that the warning object such as the stopping vehicle isjudged.

[0139] Then, according to a path judgment function 78 by the navigationsystem 77, it is judged whether the warning object is on the drivingvehicle lane in the future, and warning designation 15 is performed onlywhen it is judged to be on the driving vehicle lane.

[0140] Accuracy of the warning designation 15 improves hereby.

[0141] In FIG. 12, an ACC system 75 constituted by using a signal fromthe millimeter wave radar, the gyro sensor, the steering sensor, the CCDcamera and the navigation system. In the figure, an accelerating anddecelerating judgment 25 is performed based on the signal by a pathjudgment 78.

[0142] Thereby the distance between the vehicles control is performed inhighly accurate.

[0143] In the embodiment shown in FIG. 8 to FIG. 11 that mentioned theabove, it was realized to alarm for a stationary object and to controlit in highly accurate by adding the camera and the navigation system inaddition to the millimeter wave radar.

[0144] In the following embodiment, the system which used only the gyrosensor and the steering sensor is provided as the millimeter wave radarand an auxiliary sensor shown in FIG. 1 and FIG. 2.

[0145] In this case, even if it is assumed that the circumstances islimited, it may be realized to alarm and control it in highly accurateby solving the following problems.

[0146] 1. Cannot a curve to start with the forward host vehicle beestimated?

[0147] 2. Cannot estimate where of center or side of the host vehiclelane the host vehicle runs?

[0148] 3. Cannot judge whether there is a stationary obstacle on thehost vehicle lane from a relationship of transfer objects?

[0149] They will be explained based on drawings as follows.

[0150] FIGS. 13 (a), 13 (b) shows two cases that a driving vehicle movesin forward of the host vehicle into lateral direction on the road havingplural driving vehicle lanes.

[0151]FIG. 13A shows a case that the host vehicle is before the curvedroad and the forward preceding vehicle is on the curved road, and FIG.13B shows a case that the preceding vehicle changes the vehicle lane.

[0152] In FIG. 13A, the preceding vehicle is a object to be alarmed orbe followed continuously, and in FIG. 13B, the preceding vehicle becomesnot to be the following object.

[0153] When both is looked at from the host vehicle, the precedingvehicle looks to move to the lateral direction, it can be distinguishedfrom the movement of other vehicle.

[0154] In other words, forward vehicle 1 and forward vehicle 2, and thepreceding vehicle moved to the same lateral direction are detected, andit is judged to be the curved road when they moved to the same lateraldirection, and it is judged to be the vehicle lane change when theymoved to the different direction.

[0155]FIG. 14 is a flow chart showing steps to distinguish FIG. 13A andFIG. 13B.

[0156] At first in step 1401, the velocity of the preceding vehicle(d1(t), θ1(t), Vf1(t)) is detected from a distance with the precedingvehicle 1 at time t, the magnetic declination degree, and from the hostvehicle velocity and the relative velocity.

[0157] Similarly, relating to the forward vehicle 2, 3 except the hostvehicle lane, (d2(t), θ2(t), Vf2(t)), (d3 (t), θ3(t), Vf3(t)) aredetected. (The forward vehicles to be detected is determined to be twohere, however when it can be detected more, detected vehicle number maybe increased).

[0158] In a step 1402 in the next, using data of past times t-1, t-2, .. . , a differentiation filter process is performed, and the changesΔθ1(t), Δθ2(t), Δθ3(t) of θ1(t), θ2(t), θ3(t) are obtained.

[0159] In a step 1403, (Δθ1(t)/Vf1(t)), (Δθ2(t)/V f2(t)) ,(Δθ3(t)/Vf3(t)) are obtained.

[0160] These are equivalent to an angle which changes corresponding tothe driving distance of the vehicle, and it does not depend on thevelocity of each vehicle. Using this in a step 1404, a transfer distanceof the preceding vehicle and forward vehicles 1, 2 is obtained so as tobe judged by obtaining ΔM12 and ΔM13 based on equations as follows.

ΔM12=|(Δθ1/Vf1)−(Δθ2/Vf2)|

[0161] , and

ΔM13=|(Δθ1/Vf1)−(Δθ3/Vf3)|

[0162] The values of ΔM12 and ΔM13 are equal to or less than apredetermined value, it is judged to be the transfer on a curve (step1405).

[0163] On the other hand when it is bigger than the value, it is judgedto be the vehicle lane change (step 1406).

[0164] An example is shown here, in which, the host vehicle and thepreceding vehicle runs at the center of a 3 vehicle lanes, and otherones respectively run on right and left vehicle lanes.

[0165] If the forward vehicle except the preceding vehicle is caught onor more than two vehicle lanes, a similar estimation may be performed.

[0166] However, estimation accuracy improves further when the morevehicles are captured.

[0167] Although the hypothesis is different from a cases that theforward vehicle especially changes the vehicle lane, such a falseestimation can be avoid by increasing captured vehicle.

[0168] By the way in FIGS. 13(a) or (b) figure, in the host vehicle laneestimation, the vehicle lane position of the preceding vehicle is judgedby supposing that the host vehicle run the vehicle lane center.

[0169] For example, as shown it in FIG. 13A, the preceding vehicle andforward vehicle run at the vehicle lane center, and the lateral positionof each vehicle is almost equal to the vehicle lane width Ly, there isnot a problem.

[0170] However, as in FIG. 13B, when the host vehicle, the precedingvehicle, and the forward vehicle deviate to one end of the vehicle lane,it becomes difficult to understand which is the preceding vehicle.

[0171] Including this case, the driving position to the white line ofthe host vehicle is estimated, and it is important to reflect it to thepreceding vehicle judgment by offsetting the range of the host vehiclelane to the right or the left.

[0172]FIG. 15 shows a flow chart relating to a method to estimate thehost vehicle position and to offset the host vehicle lane position tothe right or the left based on the estimated host vehicle position.

[0173] At first in a step 1601, the lateral position YL(t), YR(t) of theright and the left forward vehicle, are obtained except one vehiclewhich is recognized as the preceding vehicle. (When it cannot be judgedas shown in the FIG. 13B, one in a side which the magnetic declinationis small, is judged to be the preceding vehicle.)

[0174] In a step 1602, a moving average values <YL(t)>, <YR (t)> ofYL(t) , YR(t) which are sampled a predetermined times in the past.

[0175] In step 1603, corresponding to <YL(t)>, <YR(t)>obtained,Ly+ΔLy<{(<YL(t)>+<YR(t)>)/2>}<Ly−Δ1y is judged. (Here Ly: one vehiclelane width, ΔLy: value to be smaller than the one vehicle lane width).When the condition is not satisfied, it is assumed that reliability ofthe data is low, and it is not adopted.

[0176] When the condition is satisfied, the step 1604 is absorbed and isjudged according to the next equation.

[0177] When {<YL(t)>−Ly}>ΔLy and {<YR(t)>−Ly}<ΔLy it is judged as aright side moving.

[0178] When {<YL(t)>−Ly}<ΔLy and {<YR(t)>−Ly}>ΔLy it is judged as a leftside moving.

[0179] When {<YL(t)>−Ly}<ΔLy and {<YR(t)>−Ly}<ΔLy it is judged as acenter.

[0180] In a step 1605, the range of the host vehicle lane judgment isoffset to the right side or to the left side, or it is judged to bemaintained according to the result.

[0181] The above is a case in which the vehicles run at the center ofthe three vehicle lanes, and even if it is two vehicle lane or a forwardroad it is possible to be similar.

[0182] In this case, the forward vehicle in only one side or transversedirection distance with the forward vehicle are used for a reference,and reliability is improved by increasing number of the sample.

[0183] Further, in this method, because of a problem relating to aninstallation of the millimeter wave radar, even if when it must bemounted on the right or the left of the vehicle, it can be revised byestimating automatically.

[0184] A case that the preceding vehicle moves to the transversedirection and the stationary object appeared over there, will beexplained in the next.

[0185]FIGS. 16A and 16B show a case that the preceding vehicle moves tothe transverse direction and the stationary object appeared over there.

[0186] Basically, an alarm is generated in FIG. 16A, and it is notgenerated in FIG. 16B.

[0187] However, because a course forward cannot be predicted, they cannot be distinguished.

[0188] Then, FIG. 17 shows a method to plan to distinct the both bypaying attention to the transverse moving velocity of the precedingvehicle and the pattern.

[0189] When, the transverse moving velocity of the preceding vehicle isshown with a relationship with time as shown in the figure, the curvedroad is detected showing a gentle change, however, in case of vehiclelane change, the velocity is large at first because the steering angleis large, and the lateral direction velocity disappears because thesteering is returned after the vehicle lane change, so that it isdetected as a variation of a convex shape.

[0190] The host vehicle closes to the stationary object while detectingthe movement of the preceding vehicle, and a timing to alarm judgment attime T1, T2, and T3 according to the vehicle velocity of the hostvehicle and the distance between the cars, becomes different.

[0191] In cases of T2, T3, the judgment is easy, and the both can bedistinguished easily by detecting a changing pole point P of thepreceding vehicle driving speed.

[0192] On the other, in time T1, the both is needed to be distinguishedon the basis of one threshold value.

[0193] This threshold value is changed at any time according to the hostvehicle velocity, the preceding vehicle velocity, the preceding vehiclemagnetic declination degree, the host vehicle angular velocity and thedistance between the vehicles.

[0194]FIG. 18 shows a case that an oncoming vehicle goes across thestationary object which is more distant than the oncoming vehicle.

[0195] In such a case, it is not considered to be the stationary objectwhich is on the host vehicle lane and the alarm is not generated.

[0196] In such a method, the oncoming car is captured in a magneticdeclination degree neighborhood of the stationary object caught atfirst, if the distance between the vehicles is closer than thestationary object, the stationary object is considered to be outside ofthe vehicle lane and it is not an object to be generated the alarm.

[0197] In this case, this judgment is performed on the basis of a timedifference that caught the stationary object and the oncoming vehicleand by correcting the movement of the host vehicle.

[0198] As stated above, in the present invention,

[0199] A correct estimation equation of the preceding vehicle positionis provided, and a device which used it is proposed.

[0200] The correction amount is changed at an introduction part of thecurve: angular velocity generation early stage (an increase direction),and at a rear part of the curve: angular velocity generate later stage(a decrease direction).

[0201] On the basis of the sensing positions of plurality of thepreceding vehicles, white line position is estimated.

[0202] The curve forward and the branching are judged by detecting themovement amount in the lateral direction of the forward vehicle.

[0203] Judgment of the host vehicle lane and the position correction ofthe preceding vehicle are performed by using both of the gyro sensor andthe steering sensor.

[0204] The lane position judgment of the preceding stationary object andpresence judgment of the stationary object warning are performed bymovement of the preceding vehicle.

[0205] The lane position of the preceding stationary object is judged bya relation with the oncoming vehicle.

[0206] The stationary object which is detected forward is recognized tobe a stationary target on the road and the warning is not generated whenit is the stationary target.

[0207] When the stopping vehicle is captured on the driving lane, thedriving lane is judged whether it is a driving route of the host vehicleor not, and if it is judged to be the driving route of the host vehicle,a warning is generated.

[0208] A one body type millimeter wave radar system building in acommunications network facility and a judgment control function.

[0209] [Effect of the Invention]

[0210] As being constructed as above, the present invention has effectsas follows.

[0211] Distance of the host vehicle with the preceding vehicle iscontrolled to become a desired value, by detecting a preceding vehicleon a host vehicle lane(including a stopping vehicle) using a millimeterwave radar, or when the host vehicle comes too much close with thepreceding vehicle, a collision warning is generated.

[0212] In addition, a warning or the control (deceleration) can beperformed only the forward stopping vehicle of the host vehicle lane, bydistinguishing the stopping preceding vehicle from the road sign on theroad side and the stationary object such as the overhead bridge.

[0213] On the basis of movement of the preceding vehicle which the radarcaught and other sensor information, an accurate host vehicle laneestimation and a position correction of the vehicle can be performed ina curve road.

[0214] The lane position estimation of the preceding vehicle isperformed by receiving various data from the vehicle side and bycombining it with the sensing information obtained by the millimeterwave radar, a warning and a control command information can betransmitted to the vehicle side.

What is claimed is:
 1. A vehicle control method comprising the steps ofdetecting a velocity and angular velocity of a host vehicle, and adistance and a direction from said host vehicle to a preceding vehicleor a target, calculating a next distance from said host vehicle to saidpreceding vehicle or said target based on said velocity, angularvelocity and said direction detected in the former step, and controllingsaid host vehicle so as to decelerate said host vehicle when said nextdistance is smaller than a predetermined value.
 2. A vehicle controlmethod as defined in claim 1, said vehicle control method characterizedin that said predetermined value is smaller than a half of a vehiclelane.
 3. A vehicle warning method comprising the steps of detecting avelocity and angular velocity of a host vehicle, and a distance and adirection from said host vehicle to a preceding vehicle or a target,calculating a next distance from said host vehicle to said precedingvehicle or said target based on said velocity, angular velocity and saiddirection detected in the former step, and generating a warning whensaid next distance is smaller than a predetermined value.
 4. A vehiclecontrol method as defined in claim 1, said vehicle control methodcharacterized in that said predetermined value is samller than a half ofa vehicle lane.
 5. A vehicle lane position estimation device forcapturing a preceding vehicle or a target by searching forward of anhost vehicle and estimating vehicle lane position thereof, said vehiclelane position estimation device comprising a means for measuring adistance TR between said host vehicle and said preceding vehicle or saidtarget, a direction angle α from said host vehicle, an angular velocityWs and a velocity Vs of said host vehicle, one vehicle lane sensingmeans for obtaining a lane Ly of a road, a means for calculating alateral displacement TC between said host vehicle and said precedingvehicle or said target, a longitudinal displacement TD therebetween anda curvature radius R of said host vehicle based on a following equationT _(C) =T _(R) sin α, T _(D) =T _(R) cos α, R=Vs/Ws, a means forcalculating lateral distance ΔR between said host vehicle and saidpreceding vehicle or said target based on a following equation,ΔR={square root}{square root over ((R−Tc)2+Tp2−R)}  (Equation 1) a meansfor comparing Ly/2 with ΔR, and a means for judging said precedingvehicle or said target to be in a vehicle lane of said host vehicle when1 ΔR1<Ly/2.
 6. A vehicle lane position estimation device as defined inclaim 5, further comprising a means for judging whether a curve of saidroad is a transition curve section where a curvature radius thereofchanges every moment sometimes, or a maximum curve section where saidcurvature radius does not changes, and a means for correcting acurvature radius Rs of said host vehicle used for correcting saidcurvature radius Rf of said preceding vehicle to be smaller than apredetermined value when a transition curve is in an introduction partof the curve, and for correcting said curvature radius Rs to be largerthan said predetermined value when said transition curve is in an rearpart of the curve.
 7. A vehicle lane position estimation device asdefined in claim 5, further comprising a means for obtaining a judgmentposition of a vehicle lane of said host vehicle by estimating a vehiclelane position of plural said preceding vehicle and making a vehicle lanejudgment position of said preceding vehicle offset towards right or leftaccording to said vehicle lane position estimated.
 8. A vehicle laneposition estimation device as defined in claim 5, wherein a millimeterwave radar and a gyro sensor are used as said means for measuring.
 9. Avehicle lane position estimation device as defined in claim 5, wherein asteering sensor and a gyro sensor are used as said means for measuring.10. A vehicle lane position estimation device as defined in claim 5,wherein a CCD camera and a navigation device having a route guidancefunction are used as said means for measuring.
 11. A vehicle laneposition estimation device as defined in claims 5 to 10, furthercomprising a means obtaining a distance of the vehicles from saidpreceding vehicle, and a means for warning when said distance becomes apredetermined distance.
 12. A vehicle lane position estimation devicefor estimating a position of a vehicle lane of a stationary object (aforward stationary object) to be located before an host vehicle,comprising a means for measuring a distance between said host vehicleand said preceding vehicle or an oncoming vehicle, a direction anglefrom said host vehicle, an angular velocity and a velocity of said hostvehicle, one vehicle lane sensing means for obtaining a vehicle lane ofa road, a means for calculating a lateral displacement between said hostvehicle and said preceding vehicle or said oncoming vehicle, alongitudinal displacement therebetween and a curvature radius of saidhost vehicle, a means for capturing a forward stationary object, a meansfor obtaining a movement of said preceding vehicle or a position of saidoncoming vehicle, a means for estimating a vehicle lane position of saidforward stationary object from a movement relationship of said precedingvehicle obtained and said forward stationary object captured or aposition relationship with said oncoming vehicle, and a means forwarning when said forward stationary object is in a vehicle lane of saidhost vehicle.
 13. A vehicle lane position estimation device as definedin claim 12, further comprising a means for calculating lateral distanceΔR between said host vehicle and said forward stationary object based onfollowing equations T _(C) =T _(R) sin α, T _(D) =T _(R) cos α, R=Vs/Wsand ΔR={square root}{square root over ((R−Tc)2+Tp2−R)}  (Equation 1)wherein T is a distance between said host vehicle and said forwardstationary object, a angle from said host vehicle, Ws velocity of saidhost vehicle, Vs velocity of said host vehicle, Tc lateral displacement,TD longitudinal displacement, and R curvature radius of said hostvehicle.
 14. A vehicle lane position estimation device as defined inclaim 12 or 13, further comprising a means for recognizing whether saidforward stationary object is an object on the road such as an overheadbridge.